Dim led power supply with constand current 12VDC 300W-IP67

Hello,

A customer asks to dim his led strips , but the led strips are powered with a led power supply with constand current.
(the installation is a total of 30m led strips ) 3 supply’s of 300w

I tryed to dim the whole installation with a modulair niko dimmer 1400va , but the dimmer flew in alarm.
But if i try the dimmer with one led strip (and the constant power supply) of 5 m its no problem .

Can i dim the ( led power supply with constand current 12VDC 300W - IP67) ?

Maybe with an old skool dimmer ? or can i simply not dim this device ?

thanks for the advice !

Are the power supplies dimmable?
If yes, with what kind of dimmer (leading or trailing edge)?